A number of industrial cleaning processes are known. For example, U.S. Pat. No. 4,136,217 (Henley 1979) discloses cleaning oil-in-water emulsions from aluminum cans during their manufacture using an acidic or alkali wash which also includes a de-emulsifier. Henley further discloses separation of the oil washed from the cans and recycling of the entire wash solution with the emulsifier without separation of its components and without recycling of any rinse streams.
U.S. Pat. No. 4,599,116 (King et al. 1986) discloses a process for cleaning aluminum cans which uses an alkaline wash solution for removal of organic soils followed by rinsing with water wherein the rinse water is maintained at neutral or acidic pH to avoid discoloration of cans by alkaline buildup in the rinse water.
A number of references also disclose various cleaning systems which include some type of recycle streams for varied applications. For example, U.S. Pat. No. 3,951,682 (Schevey et al. 1976) discloses a multi-phase rinse and recovery process for cleaning aqueous plating salt-containing solutions from plated articles. The plating salt-containing solution is rinsed with a mixture of two liquids, one of which is not miscible with the plating salt-containing solution. The drained solutions are collected and the immiscible liquid is allowed to separate from the two miscible liquids and the two phases can be recycled.
Other references show the use of terpene-based solutions as cleaning agents. For example, U.S. Pat. No. 4,511,488 (Matta 1985) discloses a d-limonene based aqueous cleaning composition containing between 10 and 60 wt. % d-limonene, between 10 and 30 wt. % surfactants and between 20 and 70 wt. % water for use in cleaning hard and/or flexible substrates, such as surfaces in machine shops, auto service centers, and food processing industries. This reference also discloses that after cleaning, materials such as oils or greases can be allowed to separate from the cleaning solution and that the cleaning solution, including d-limonene, surfactants and water, can be reused without separation of its components and without recycling of any rinse streams.
Another illustrative reference disclosing the use of d-limonene as a cleaner is U.S. Pat. No. 4,640,719 (Hayes et al. 1987) which discloses a method for cleaning solder flux, oils, waxes, greasy substances, and/or adhesive tape residues from printed wiring boards or printed circuit boards.
Despite the large number of references generally dealing with industrial cleaning processes, a need exists for an integrated terpene-based cleaning system which allows for operation in which all liquid cleaning and rinsing streams can be recycled.